Actors are pictured at the rehearsal of Wolfgang Amadeus Mozarts "La Clemenza di Tito" at the Felsenreitschule in Salzburg, on July 21, 2017 during the 97 Salzburg Festival. BARBARA GINDL / APA / AFP.

SALZBURG(AFP).- Austria's Salzburg Festival opened Saturday, the start of more than a month of classical and dramatic performances featuring some of opera's brightest and most controversial stars.

A highlight of the 40-day festival will come on August 6 with a production of Verdi's masterpiece "Aida", directed by Iranian artist Shirin Neshat.

Organisers expect around a quarter of a million visitors to flock the city of Mozart's birth to take in performances from classical music luminaries such as Simon Rattle, John Eliot Gardiner and Mariss Jansons.

High points will include a modern retelling of Mozart's "La Clemenza di Tito", conducted by classical music's enfant terrible Teodor Currentzis and directed by Peter Sellars.

One of the events more surreal moments will come when Italian mezzo-soprano Cecilia Bartolia dons a false beard to play the title character in Handel's "Ariodante" -- a part originally performed by male castrati.

The festival's musical events get underway Saturday evening with American conductor Kent Nagano leading the Bavarian Radio Symphony Orchestra through Olivier Messiaen's "The Transfiguration of our Lord Jesus Christ."

The 1960s showpiece is rarely performed live as it requires around 200 performers.